Here's a picture of our wet bath to give you an idea of its size.

As you can see, it's easy to bump the faucets with your knee when sitting on the toilet, trying to wipe your backside. What you can't se from the photo is the sloping A-frame ceiling ust out of the picture that makes it impossible to stand and urinate. One must sit down for #1, #2 or to shower.
I'm sure they come in different sizes though, we just happen to have a tiny one. The Chalet A-frames that use a wet bath in the center of the camper, where one can't even reach the ceiling on tip-toes, are a little bigger and easier to use - but you can't tow them with a 4 cylinder car either. Life is a series of trade-offs - you must give up something to get something else you want more.
Chip